Tamperproof Cap For Sealing Bottles Using A Stretchable Plastic Polymer Membrane On A Hollow Frame Within A Preformed Rigid Cover

ABSTRACT

A cap for the hygienic sealing of bottles for drinkable liquids, which in one embodiment includes a closed bottom cylindrical, i.e. cup-shaped, aluminum sleeve, an insert composed of a lower hollow cylindrical base, a truncated cone also having a hollow shape, and a tapered wall having two or more elongate and vertical apertures formed therein. Said cap is further characterized by a stretchable plastic membrane that is stretched to externally cover the truncated cone-shaped section of said insert as well as its top opening, by an elastic plastic ring for clamping said membrane against the insert, and by an additional plastic structure concentric with the sleeve that sealingly occupies at least its closed bottom and acts as a seal.

FIELD OF THE INVETION

The present invention relates to a tamperproof cap for a liquid container. More particularly, the present invention relates to a tamperproof cap that includes a strechable membrane disposed in its interior.

BACKGROUND OF THE INVENTION

A variety of methods are used in the prior art to seal or close bottles, some of which use tamper detection arrangements of questionable efficacy.

Furthermore, most of the tamperproof methods in the prior art are either expensive, ineffective, or unsuccessful in fulfilling their intended purpose, and may not provide the desired liquid tightness to prevent the ingress of contaminants over time. For the sake of brevity, only the best known and most widely used bottle closure system will be discussed herein, which includes a metal or plastic capsule that is permanently secured by various arrangements to the neck of the bottle and that cannot be removed without being damaged. This capsule has an upper section that can be only unscrewed after tearing a weakened annular section, e.g. that has a succession of holes or cutouts. This cap or closure can only provide liquid tightness by using an elastic seal between the closed bottom of the unscrewable section and the annular edge of the opening of the bottle.

While these methods in the prior art, which are nearly equivalent in terms of liquid tightness due to the use of variously thick and shaped elastic seals, provide certain advantages, such as a relatively low cost and a well-established fabrication technology resulting from functional standadization of capping machines, such methods still do not meet all current needs for a tamperproof cap i.e., in order of importance: time-dependent and absolute impermeability to solid, liquid and gaseous contaminants, positive tamper evidence, simple application and reasonable costs.

In general, current closures for bottles mostly provide more or less acceptable compromises, as nothing has been found heretofore to solve the tamper problem in a generally applicable and cost-effective manner.

Low-cost requirements often influence the selection of the tamperproof closure, such requirements being a function of the value of the content of the bottle, as well as of the market size and the profit margin therefor. For example, mineral waters generally have a very large market but their profit margin, which depends on the content of the bottle, requires compromises to be made in the fabrication and application of closures. Instead, valuable beverages, such as spirits or special soft drinks, exotic syrups or special alcohol or non-alcohol beverages, have a smaller market but their unit profit margin is higher and justifies the use of more complex and a fortiori more expensive capping, which often enhances product image and adds value thereto, besides improving efficiency. Nevertheless, these special and more expensive closures are not distinctly more effective as compared with market standards.

SUMMARY OF THE INVENTION

While the cap of the present invention cannot be used cost-effectively for all types of products, a good integrated solution is provided that reasonably integrates absolute impermeability over time to all contaminants, evidence of any tampering of the bottle, easy capping, and a reasonable cost.

This result has been achieved, in one embodiment, by a suitable combination of the following components of the cap:

-   -   a) An external cup-shaped rigid structure or cover, made of an         aluminum or plastic material and adapted to be non removably         secured to the neck of the bottle as described hereafter in         various embodiments.     -   b) Three further elements common and essential to all         embodiments, i.e.

b1) An insert 3 or frame made of an elastic or sufficiently rigid plastic polymer, i.e. having a resilient behavior in response to the deformations expected in its various parts, and composed of a hollow cylinder which extends upwards (the upward direction corresponding to the upward direction of the bottle, i.e. of its opening) extending as a truncated cone, also having a hollow shape, whose wall has two or more vertical elongate apertures formed therein, which are symmetrical with respect to the axis of the insert and open at the minimum diameter thereof, and which allow the tapered wall surfaces delimited thereby to be elastically deformed at their ends in radial directions

b2) A membrane of a stretchable plastic polymer (polyethylene, polyvinylchloride, ethyl vinyl acetate, etc.), which is stretched to cover the outer side of said insert and also the opening of its upper section at its minimum diameter.

b3) A ring made of a resilient plastic material, which is designed to be fitted into an annular groove having a section complementary thereto, and formed in the cylindrical wall against which the ring will compress the base of the membrane stretched over the insert.

c) Another plastic frame or structure 6, concentric with the external rigid structure, which, in the different embodiments, may wholly or partly cover the inner cylindrical side as well as the closed bottom of the structure, or even the bottom only, thereby simply acting, in the latter case, as a seal.

An important functional element is common to all embodiments. This element is the process performed by the insert with the membrane stretched thereon, which consists in laying such membrane on the mouth of the bottle during capping, i.e. by the axial capping motion, so that it adheres thereto thanks to its shrinking ability, i.e. thanks to the vertical stretching effect on the surface of the stretchable plastic polymer in contact with the truncated cone. During capping, an annular stress is generated in the structure of the membrane, which causes the surface of revolution of the membrane to be shrunk around the mouth, thereby providing the required adhesion thereto. Such adhesion is caused by the removal of the boundary air layer from the contact area between the membrane and the mouth, which allows the atmospheric pressure to be transferred to the contact surface, and to generate sufficient shearing stresses to ensure adhesion. The capping process stops when the mouth, with the membrane thereon, contacts the seal that may or may not be part of the structure lying on the closed bottom of the rigid aluminum sleeve. Then, the membrane elastically seals the opening of the bottle and adheres thereagainst in such a manner as to ensure long-lasting impermeability of the cap to the various solid, liquid and gaseous contaminants.

A further advantage of the present invention is an additional tamperproofing function of said membrane, which will remain unbroken as the bottle is opened, wherefore irreversible tearing thereof is required to access the content of the bottle.

The most efficient embodiments of the invention will be now described, although each of them may be better than the other embodiments for specific uses only. Therefore, the order of such descriptions is not related to any classification of efficiency.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Turning now to the annexed drawings:

FIGS. 1 and 1 a are different views of a first variant embodiment of this invention, showing the insert 3;

FIGS. 2 and 2 a are different views of a cap having a reduced structure 6 and threads 11;

FIG. 3 shows a cap having a reduced structure 6 and flaps 10;

FIGS. 4 and 4 a show a cap having a structure 6 with a seal 16 and threads;

FIG. 5 shows a cap having a structure 6, flaps 10 and a support 7 c for the insert 3;

FIGS. 6 and 6 a show a toothed insert 3;

FIGS. 7 and 7 a show an insert 3 having a wavy top;

FIGS. 8 a, 8 b, 8 c, 8 d, 8 e, 8 f, 8 g, 8 h, 8 i show different caps and bottle necks;

FIGS. 9 and 9 a show a neck of the bottle 1 with three sub-necks 7 a, 7 b and 7 c;

FIGS. 10, 11 and 12 show different sections of embodiments of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

According to a first embodiment of the invention, shown in FIGS. 1 and 2, a cap includes an aluminum sleeve 2 having a length of 45 to 70 mm with the bottom edge 2 c folded a few millimeters inwards. A structure 6 is sealingly received in said sleeve 2 and held therein by sealing deformations or protrusions or extrusions 8 of the sleeve 2, and consists of a plastic cover having threads formed in the inner wall at its bottom. Such threads 11, which may be also segmented, are molded by usual techniques. In addition to such threads 11, the structure 6 has one or two circular concentric ridges 15 on its inner bottom for better adhesion thereof, as a seal, to the mouth of the bottle 1. This structure 6 may either have its height limited to the screwing length covered by its threads or sealingly cover the whole length of the inner side of the aluminum sleeve 2.

In this and in all other embodiments, the caps have an insert 3 covered by a stretchable plastic polymer membrane 5 compatible with its specific organoleptic use, which is stretched over the cylindrical wall 3 a, the conical wall 3 b and the opening 3 c at the minimum diameter thereof.

Such insert 3 holds the membrane 5 at its cylindrical bottom 3 d by means of a ring 5 a, which compresses the membrane 5 against the outer cylindrical wall of the insert 3 on a segmented annular area whose section is complementary to the inner section of the ring 5 a. The insert 3, with the membrane 5 thereon, is sealingly received within the sleeve 2 or the structure 6 within the sleeve 2. The insert 3 may lie either, in a first variant of this embodiment, by its bottom 3 d on the inwardly folded bottom 2 c of the sleeve 2 or, in a second variant, against the upper rim of an annular protuberance 7 c molded on the neck of the bottle 1.

In the first variant of the present first embodiment of the cap, the bottle 1 has a single sub-neck or annular protuberance 7 b, which is configured to vertically lock the conical end 3 c of the insert 3, as set forth below.

Conversely, in the second variant of the present embodiment, the bottle 1 has two sub-necks or annular protrusions 7 b and 7 c, the conical end 3 c of the insert 3 being vertically locked by 7 b and the bottom 3 d of the insert 3 being locked by 7 c.

Still in the first variant, as shown in FIG. 2, the structure 6 may have its height limited to the screwing length covered by its internal threads 11. In the second variant, as shown in FIG. 5, a structure 6 will be preferably used, whose length will cover the entire inner length of the aluminum sleeve 2.

In both variants, the internal diameter of the folded bottom 2 c of the sleeve 2, on which either the bottom 2 d of the insert 3 or the free bottom of the structure 6 abut, shall precisely adhere against the diameter of the neck of the bottle 1 with the cap applied thereon. This embodiment further provides a weakening arrangement 9 on the sleeve 2 along a circumference below the threads, which is designed to be torn off as the bottle 1 is opened.

An aspect of this embodiment is that capping occurs by screwing when the membrane 5 is already stretched across the rim of the bottle 1, wherefore such membrane 5 is subjected to non negligible shearing stresses during screwing. This drawback is mainly solved by using thicker and more stretchable membranes 5 in combination with worms having more rounded and wider threads 11. According to a second embodiment of the invention, shown in FIGS. 3, 4 and 4 a, the cap still includes an aluminum sleeve 2 typically having a length of 40 to 65 mm with the bottom edge 2 c folded a few millimeters inwards. A structure 6 is sealingly received in said sleeve 2 and held therein by deformations 8 of the sleeve 2, and consists of a plastic cover sealingly introduced in the sleeve 2 and having flaps 10 at its closed bottom, i.e. radially movable portions of the cylindrical wall of the structure 6. In a first case, this mobility is obtained by forming three cuts, preferably but without limitation orthogonal to each other and continuous, which delimit a rectangle or a trapezium whose fourth side is integral with the cylindrical wall of the structure 6. Thus, these flaps are able to elastically rotate about this fourth side. All the vertical sections of these flaps 10 contain a protuberance 12 of triangular section with a 90° angle at the free apex, whereas the upper side forms an angle of about 35° with the plane perpendicular to the axis of the cap. Therefore, a horizontal crest is formed, which extends all along said flaps 10.

In a second variant of the present embodiment, the flaps 10 are integral with the cylindrical wall of the structure 6 not only along the lower side but also along the two horizontal sides, i.e. the upper and lower sides of the rectangle or trapezium, whereas the vertical sections of the flaps 10 are identical to those of the first case. From a mechanical point of view, the flaps have the elastic bending behavior of a cantilever beam in the first variant, and of a beam supported at its ends in the second variant.

In both variants, these flaps are designed to snap fit into an annular extension (7 b) surrounding the neck of the bottle 1 as the cap is vertically pressed against the opening for closing the bottle 1.

This embodiment also includes an insert 3 to be sealingly introduced in the structure 6 and covered by a membrane 5, which is stretched and retained by a ring 5 a against the bottom 3 d of the outer cylindrical wall of the insert 3. Such insert 3 may lie by its bottom 3 d on the folded bottom 2 c of the sleeve 2, in which case it will be vertically retained thereon by an annular recessed step 20 (see FIG. 2) formed in the sleeve 2, whereas the structure 6 will have its height limited to the upper portion of the sleeve 2, i.e. the one comprising the flaps 10 or deformations 8 that hold the structure 6 within the sleeve 2. In the second variant (see FIG. 5), in which the insert 3 lies by its bottom 3 d on an annular protuberance 7 of the neck of the bottle 1, the structure 6 covers the whole length of the sleeve 2 and lies against the folded bottom 2 c thereof, and holds the insert 3 therein by means of an annular groove .

In the first variant, a suitable bottle 1 has two annular protuberances 7 a and 7 b: the former shall be engaged by the flaps 10 and the latter shall upwardly lock the conical end 3 c of the insert 3. In the second variant, the bottle 1 shall have three annular protuberances 7 a, 7 b and 7 c: the first shall be engaged by the flaps 10, the second shall upwardly lock the conical end 3 c of the insert 3, and the third shall act as a support for the base 3 d of the insert 3.

This second embodiment also provides an annular weakening arrangement 9 on the sleeve 2.

For simplicity and cost reduction requirements, the two embodiments described above may be also provided without an aluminum sleeve 2.

In this case, the insert 3 will be locked within the structure 6 which will itself act as the main structure of the cap, whereas the weakening arrangement 9, already formed in the complete structure 6, will be that formed in the cylindrical wall of the external structure. In all the above embodiments, the insert 3 is prevented from rotating as the cap is screwed and/or unscrewed by using an insert 3 with a bottom 3 d having teeth 17, whose spacings are designed to engage with particular complementary protuberances 18 of the outer wall of the neck of the bottle 1. In other embodiments, still with the purpose of preventing circular slipping, inserts 3 may have vertical raised ribs 19, which fit into corresponding grooves formed in the inner walls of structures 6 or aluminum sleeves 2.

According to a third embodiment, shown in FIGS. 4 and 4 a, the cap includes an aluminum sleeve 2 typically having a length of 40 to 65 mm with the bottom edge 2 c folded a few millimeters inwards. The closed bottom of such sleeve 2 receives an elastic seal 16, possibly formed by one or more annular protuberances designed to contact the opening of the bottle 1 so to optimize liquid tightness. This embodiment does not include a structure 6 but also includes an insert 3 to be sealingly introduced in the aluminum sleeve 2 and covered by a membrane 5, which is stretched and retained by a ring 5 a against the bottom 3 c of the outer cylindrical wall of the insert 3. This insert 3 may lie by its bottom 3 d on the folded bottom 2 c of the sleeve 2, as shown in FIG. 4, in which case it will be vertically retained and locked thereon by an annular recessed step 20 formed in the sleeve 2. Otherwise, the insert 3 will lie by its bottom 3 d on an annular protuberance 7 of the neck of the bottle 1 and will be also vertically upwardly retained by a recessed step 20 formed in the sleeve 2. In this embodiment, the cap will be connected to the neck of the bottle 1 by screwing. Thus, the opening of the bottle 1 will have a screw thread and the complementary screw thread on the cap will be formed by a direct embossing in the body of the aluminum sleeve 2. Here again the cap has an annular weakened area 9 below the screw area 1 which will be torn off upon opening.

According to a feature common to all the above embodiments, a more efficient application of the membrane 5 has been provided by he insert 3. Liquid tightness and sealing of the bottle 1 along the rim of its opening is obtained thanks to the particular application of the ready-for-use stretchable plastic polymer membrane 5. Such application provides for an excellent sealing effect thanks to interdependent orthogonal deformations occurring as the membrane 5 is vertically and downwardly stretched along the neck of the bottle 1. During such stretching operation the membrane 5 is vertically elongated, whereby the length of its annular transverse development tends to be reduced, i.e. its vertical elongation partly reduces its development orthogonal to such elongation. In fact, the elongation caused by a vertical pulling action creates a surface of revolution whose axis coincides with that of the insert 3. The horizontal sections of this surface are circles of variable diameters along which the membrane 5 is stressed by elastic forces, increasing with decreasing diameters, which are exerted tangentially and tend to reduce the diameter of such surface.

Once the membrane 5 has been appropriately stretched, the annular resilient stress at the mouth of the bottle 1 allows firm adhesion thereof against the outer rim of the opening. Such adhesion generates a pressure of the membrane 5 against the opening, whereby the compressed boundary air layer between the membrane 5 and the opening rim of the bottle 1 is removed. Hence, atmospheric pressure may freely act on the membrane 5 which will be compressed against the opening and will firmly resist the shearing stresses at the interface, which are proportional to the contact surface and to the local coefficient of friction. These forces will elastically hold and seal the membrane 5 against the mouth. In view of this configuration, the insert 3 has been provided to optimize such effect.

Thanks to the insert 3, a pre-stretched, hood-like membrane 5 is applied, which has a flat surface at the top of the insert 3 and a vertical lateral surface along the conical and cylindrical walls 3 a, 3 b, which will be vertically stretched during capping. To this end, the vertical length of the membrane 5 provides considerable elongation without tearing. The action of screwing or engaging the flaps with the neck of the bottle 1 to secure the cap on the bottle 1 will keep the membrane elastically stretched across the rim of the bottle 1 and ensure sealing thereof. As the bottle 1 is opened, thereby causing simultaneous annular tearing of the weakened area 9, the opening is still closed by a portion of the membrane 5, which is stretched and fixed to the rim, thereby providing an evidence of sealing and indicating that no tampering has occurred.

LIST OF REFERENCE CHARACTERS

1) Bottle;

2) Aluminum sleeve;

2 a) Cylindrical section of the sleeve;

2 c) Edge or bottom of the sleeve;

3) Insert;

3 a) Cylindrical section of the insert;

3 b) Conical section of the insert;

3 c) Top opening of the insert;

3 d) Bottom of the insert;

4) Aperture formed in the insert;

4 a) Sectors of the insert;

5) Stretchable membrane;

5 a) Ring;

5 b) Housing;

6) Structure;

7 a) Upper sub-neck;

7 b) Intermediate sub-neck;

7 c) Lower sub-neck;

8) Sealing extrusions or deformations or protrusions;

9) Weakened area in the cylindrical wall;

10) Elastic cap locking flaps;

11) Threads or worms or screw thread;

12) Teeth or ridges or protuberances of the elastic flaps 10;

14) Wavy band of the insert 3;

15) Sealing protrusions or circular concentric ridges;

16) Seal;

17) Teeth of the insert 3;

18) Protrusions or protuberances of the bottle for the teeth 17;

19) Ribs of the insert 3;

20) Step in the sleeve 2. 

1. A cap for hygienic sealing of a bottle, the cap comprising: a cylindrical sleeve having a closed end and an open end, the open end having an inwardly projecting edge; an insert disposed for at least partially within said sleeve, the insert comprising a lower hollow cylindrical base extending to form a truncated cone also having a hollow shape, the truncated cone tapering upwards and inwards a tapered wall of the truncated cone having two or more elongated longitudinal apertures formed therein, that delimit sectors having surfaces of rectangular or trapezoidal parallelepiped shapes, the sectors having at least one end integral with the lower hollow cylindrical base, the sectors being further configured to elastically open and assume an angular position from a longitudinal axis of the cap; a membrane stretchable to externally cover the truncated cone and an opening formed at a narrower end of the truncated cone; an elastic ring configured for clamping the membrane against a housing complementary to the ring, the housing being formed in an outer wall of the lower hollow cylindrical base; a structure sealingly disposed within the sleeve at least at the closed end, such to provide adhesion against the sleeve and liquid tightness of the cap; and means for securing said cap to the bottle, the means for securing being located at and/or near the closed end and between the closed end and the insert.
 2. The cap as claimed in claim 1, wherein the narrower end of the truncated cone is dimensioned to contact a neck of the bottle by contacting an annular sub-neck of the bottle that surrounds an outer portion of the bottle and that is integral with the neck of the bottle, the lower hollow cylindrical base of the insert having an end that lays against the inwardly projecting edge of the sleeve.
 3. The cap as claimed in claim 1, wherein the cylindrical sleeve comprises embossments forming a screw thread complementary to a screw thread of the bottle, and wherein the structure is configured as a sealing disk or ring provided against the closed end of the sleeve to ensure liquid tightness of the cap.
 4. The cap as claimed in claim 1, wherein an outer wall of the cylindrical sleeve comprises recesses extending towards the inside of the sleeve, the recesses being configured for holding the structure within the cylindrical sleeve.
 5. The cap as claimed in claim 1, wherein the structure comprises a screw thread complementary to screw thread on the bottle.
 6. The cap as claimed in claim 1, further comprising a circular weakened area formed by discontinuities along a circumference surrounding the cap, the circular weakened area providing an anti-tampering function.
 7. The cap as claimed in claim 1, wherein the structure comprises a plurality of multi-lateral elastic flaps which are radially movable and which are connected along a circumferential segment of a cylindrical wall of the structure and integrated at least along one edge with the cylindrical wall of the structure, the cylindrical wall of the structure having suitable apertures to allow radial motion of one of more free portions of the flaps, and wherein the flaps each have an inwardly protruding ridge of essentially triangular section disposed essentially perpendicularly to the longitudinal axis of the cap.
 8. The cap as claimed in claim 7, wherein the flaps have longitudinally disposed upper and lower sides integral with the cylindrical wall of the structure.
 9. The cap as claimed in claim 1, wherein a free edge of the cylindrical base of the insert comprises a plurality of teeth having tapered distal ends, wherein the teeth are configured to engage protrusions on a neck of the bottle, and wherein the protrusions are substantially as wide as gaps between the teeth thereby preventing the insert from rotating about a longitudinal axis of the bottle when the insert is in inserted position within the cylindrical sleeve.
 10. The cap as claimed in claim 1, wherein the narrower end of the truncated cone comprises a circumferential band integral thereto, and wherein the band has a wavy profile, causing a longitudinal development of the band to be longer than the circumference of the narrower end of the truncated cone.
 11. A neck of a bottle comprising; a first sub-neck disposed adjacent to an opening rim of the bottle and comprising, an annular thicker portion or protuberance on an outer wall of the neck; and a lower edge section configured to be compatible with the triangular ridges of the flaps of claim 7, wherein the neck has a height sufficient for engaging said flaps.
 12. The neck of a bottle as claimed in claim 11, further comprising one or more sub-necks longitudinally spaced from the first sub-neck or from threads on the cap, one of the one or more sub-necks being configured to lock the narrower end of the truncated cone of claim 1 and another one of the one or more sub-necks being configured to lock a free end of the cylindrical base of the insert of claim
 1. 13. The neck of a bottle as claimed in claim 11, further comprising protrusions or protuberances having a shape of a parallelepiped, lateral walls of the parallelepiped being configured to engage the teeth of claim
 9. 14. The cap as claimed in claim 7, wherein the essentially triangular section of the ridge has a first side forming an inward angle of about 90° with the cylindrical wall of the structure and a second side forming an angle of about 35° with a plane perpendicular to the longitudinal axis of the cap. 